Tubing cutter



Aug. 13, 1968 A. A. VENGHIATTIS TUBING CUTTER 2 Sheets-Sheet 2 FiledSept. 1966 2 8 6 6 7 9 9 6 3 4 E E R R w u m F F 8 O O 2 7 8 4 I 4 O a aA m/ h//////// r/ //A////// o a w 8 m O O o o o o d o 9 //Vv 4 2INVENTOR. ALEXIS A. VENGHIATTIS g r a 4m FIGURE 5 ATTORNEY United StatesPatent 3,396,795 TUBING CUTTER Alexis A. Venghiattis, Weston, Conn.,assignor to Dresser Industries, Inc., Dallas, Tex., a corporation ofDelaware Filed Sept. 9, 1966, Ser. No. 578,189 Claims. (Cl. 16655.7)

This invention relates generally to improved apparatus for cuttingtubing, pipe, or the like from the interior thereof along a planedisposed substantially perpendicularly to the longitudinal axis of thetubing. More particularly, but not by way of limitation, this inventionrelates to an improved cutter arranged to be run into the tubing on awire line and to utilize centrifugal force for maintaining the cuttersin cutting engagement with the tubing.

In completing an oil or gas well for production, a length of relativelysmall diameter tubing is disposed in the well bore with the lower endthereof situated adjacent the productive formation. Frequently, thetubing extends through one or more packers that function to isolatevarious formations Within the well bore.

Occasionally, the tubing must be removed from the well bore. In removingthe tubing, it will generally pass through one or more of the packers.Sometimes, the tubing becomes stuck and cannot be removed or, perhaps,only a section thereof is to be removed. In such instances, and if thesection to be removed must pass through the packers, it is importantthat the tubing be cut without expanding or severely burring the outsidediameter of the tubing. If such expansion or burring occurs, the tubingwill not pass through the packers without damage to or destruction ofthe packers.

Various devices have been constructed for the purpose of cutting thetubing. A great deal of difficulty has been encountered in the attemptto construct a mechanical tubing cutter due to the relatively smalldiameter through which the cutter must pass and the small area in whichthe cutter must operate. Most mechanical cutters have included some formof gear train for driving the cutting blades whereby they will performthe cutting operation. Manifestly, cutters utilizing gear train driveshave been ineffective due to their complexity and also due to theirinherent weakness when such gear trains are reduced to the sizenecessary to pass through the tubing. Cutting devices of this type havebeen efiective for use in the relatively larger diameter casing andsimilar pipes and conduits.

Explosive cutting devices have also been constructed, but they have notbeen entirely satisfactory due to their inherent tendency to deform thepipe and thereby increase the outside diameter so that the tubing willnot pass through the packers. Various forms of the explosive cuttingdevices have been constructed, but none have avoided the problem ofdeformation of the tubing.

Various forms of chemical cutting devices have also been constructed. Byand large, the chemical cutters have proved to be the most successful incutting tubing since they do not expand the tubing diameter.

This invention provides an improved tubing cutter comprising: a motorincluding a rotatable shaft; holding means responsive to the reaction ofthe motor for en gaging the tubing to prevent rotation of the motor; apair of spaced sleeves slidingly disposed on the shaft and rotatabletherewith; resilient means biasing the sleeves relatively apart; and, acutter assembly located between the sleeves and including a plurality ofsegmented cutter members arranged circumferentially around the shaft,and linkage means interconnecting the cutter members and sleeves,whereby the cutter members are moved relatively outwardly into cuttingengagement with the tubing 3,396,795 Patented Aug. 13, 1968 ice bycentrifugal force when the shaft is rotating and are biased relativelyinwardly out of engagement with the tubing when the rotation ceases.

One object of this invention is to provide an improved mechanical tubingcutter that can be utilized in relatively small diameter tubing.

Another object of this invention is to provide an improved tubing cutterthat utilizes centrifugal force for moving the cutters into cuttingengagement with the tubmg.

An additional object of the invention is to provide an improved tubingcutter for severing tubing located in a well bore and that is positionedtherein by means of a Wire line.

An additional object of the invention is to provide an improvedmechanical tubing cutter that can be easily and economicallymanufactured.

The foregoing and additional objects and advantages of the inventionwill become more apparent as the following description is read inconjunction with the accompanying drawings wherein like referencecharacters denote like parts in all views and wherein:

FIGURE 1A is a vertical, cross-sectional view of the upper portion of atubing cutter constructed in accordance with the invention and disposedin a section of tubmg;

FIGURE 1B is a vertical, cross-sectional view of the lower portion ofthe cutter disposed in the section of tubing;

FIGURE 2 is a cross-sectional view taken substantially along the line 22of FIGURE 1A;

FIGURE 3 is a cross-sectional view taken substantially along the line 33of FIGURE 1B;

FIGURE 4 is a cross-sectional view taken substantially along the line 44of FIGURE 1B; and,

FIGURE 5 is a vertical, cross-sectional view similar to FIGURE 1B, butillustrating the cutters in cutting engagement with the tubing.

Referring to the drawing and FIGURES 1A and 1B in particular, showntherein and generally designated by the reference character 10 is atubing cutter constructed in accordance with the invention. The tubingcutter 10 is disposed in the interior of a tubing 12 that is positionedin a well bore (not shown).

As illustrated, the cutter 10 is suspended in the tubing 12 on a wireline or cable 14. The cable 14 is connected by a conventional cable head16 to a hollow housing member 18 that forms a portion of the tubingcutter 10.

A motor 20 is disposed within the housing member 18 and is electricallyconnected by means not shown through the wire line 14 with a source ofelectrical energy (not shown). The motor 20 is pivotally supported inthe housing member 18 between an upper motor support 22 and a lowermotor support 24.

As illustrated in FIGURE 1A, the upper motor support 22 is restrainedagainst upward movement in the housing member 18 by a conventionalinternal lock ring 25. A spherical bearing 26 is disposed between theupper motor support 22 and the upper end of the motor 20 to permitpivotal or rotational movement of the motor 20 relative to the uppermotor support 22 and housing member 18.

A cam 28, which will be described in more detail hereinafter, isconnected with the lower end of the motor 20 by a plurality of threadedfasteners 30. A thrust bearing 32 encircles a portion of the cam 28 andis in engagement with the lower motor support 24, thereby pivotallysupporting the lower end of the motor 20 in the housing member 18.

As clearly illustrated in FIGURE 1A, the lower motor support 24 is inthreaded engagement with the housing member 18 and is therefore movablelongitudinally with respect to the housing member 18 to permitadjustment of the thrust bearings 26 and 32 supporting the motor 20. Aset screw 34 extends through the housing member 18 into engagement withthe lower motor support 24 to prevent inadvertent rotation of the motorsupport 24 after assembly of the motor in the housing member 18.

An output shaft 36, which is rotatably supported in the motor 28,extends through an opening 38 formed in the cam 28. The output shaft 36is connected with a shaft extension 40 by a threaded fastener 42 thatextends through the extension 40 and through the output shaft 36.

The housing member 18 is provided with a pair of threaded openings 44that extend through the wall thereof in diametrically opposed locations.Each of the openings 44 are provided with a threaded guide bushing 46having an aperture 48 extending therethrough.

A holding dog or plunger 50 is slidingly disposed in each of theapertures 48. The plungers 50 have a pointedouter end 52 arranged toengage the tubing 12 as illustrated in dash lines in FIGURE 2. A roundedinner end 54 on each of the plungers 50 is disposed in slidingengagement with the surface of the cam 28.

A compression spring 56 encircles a portion of each of the plungers 50and has one end connected thereto adjacent the inner ends 54. Theopposite end of each of the springs 56 is disposed in engagement with arespective one of the guide bushings 46. The springs 56 are of thecompression type so that the plungers 50 are constantly biased inwardly,whereby the inner ends 54 thereon remain in engagement with the surfaceof the cam 28 at all times.

As may be seen more clearly in FIGURE 2, the surface of the cam 28 issubstantially elliptical in configuration. The inner ends 54 on theplungers 50 are in engagement with the cam 28 along its minor axis whenthey are in the retracted position as illustrated by the solid lines inFIGURE 2.

When the motor 20 is energized to rotate the shaft 36, the motor 20 andthe attached cam 28 react to the rotation by pivoting on the bearings 26and 32 in the opposite direction, that is, into the position illustratedby the dash lines in FIGURE 2. As the cam 28 pivots, the plungers 50ride along the elliptical surface and, therefore, move outwardly as themajor axis of the cam 28 moves toward the plungers 50. When the rotationof the shaft 36 ceases, the springs 56 drive the dogs 50 relativelyinwardly, thereby returning the cam 28 and the motor 20 to the positionshown in FIGURE 1A wherein the plungers 50 are fully retracted.

Aiding in restoring the cam 28 and the motor 20 to the retractedposition are a pair of springs 58. As shown in FIGURE 1A, each of thesprings 58 has one end connected with the housing member 18 by afastener 60 and the other end connected with the motor 20 adjacent thebearing 26 by a fastener 62. As the motor 20 pivots about the bearings26 and 32, a force is imposed on the springs 58 which, when the rotationof the shaft 36 ceases, returns or restores the motor 20 to its originalposition.

As shown in FIGURE 1B, the lower end of the shaft extension 40 isjournalled in a thrust bearing 64 located in a centralizer assembly 66.The shaft extension 40 and centralizer assembly 66 are retained inassembled relationship by the engagement of a washer 68 located on theshaft extension 40 with a shoulder 70 formed in the body 72 of thecentralizer assembly 66. A nut 74 is in engagement with a threadedportion 76 of the shaft extension 40, thereby retaining the washer 68 onthe shaft extension 40.

As is more clearly shown in FIGURES 3 and 4, the shaft extension 40 issubstantially square in cross-section. However, the lower end, which isjournalled in the thrust bearing 64 and extends into the body 72 of thecentralizer assembly 66, is circular in cross-section as required.

As shown in FIGURES 1A and 1B, a pair of identically constructed, thoughoppositely disposed, sleeves 78 are slidingly located on the squareportion of the shaft extension 40. The sleeves 78 are each provided witha square aperture 80 (see also FIGURE 4) that is sized to receive theshaft extension 40. Due to the square configuration of the shaftextension 40 and the apertures 80, it can be appreciated that thesleeves 78 rotate with the shaft extension 40. A collar 82 is mounted onthe upper end of the shaft extension 40 (see FIGURE 1A) to limit theupward movement of the uppermost of the sleeves 78.

A compression spring 84 encircles the shaft extension 40 between thesleeves 78. One end of the spring 84 engages the uppermost sleeve 78 andthe other end engages the lowermost sleeve 78, whereby the sleeves arebiased relatively apart for reasons that will become more apparenthereinafter.

A plurality of hinges 86 are radially spaced about the sleeves 78. Oneend of each of the hinges 86 is connected with a respective one of thesleeves 78 in any suitable manner. The opposite end of each of thehinges 86 is connected with one end of a respective elongated member 88.As illustrated in FIGURE 1B, and when in the retracted position, theelongated members 88 extend generally parallel to the shaft extension40. The opposite end of each of the elongated members 88 is connectedwith a cutter assembly 90.

Each cutter assembly 90 includes a pair of hinge members 92 and a cutterblade 94 mounted between and con nected to the hinge members 92. Asillustrated, adjacent ends of the elongated members 88 are connectedwith the opposite end of each of the hinge members 92, whereby thecutter blades 94 are supported by an articulated linkage consisting ofthe hinge members 92, the elongated members 88 and the hinges 86 which,as previously described, are mounted on the sleeves 78.

Referring to FIGURE 3, it can be seen that each of the cutter blades 94has a toothed arcuate outer edge which, when extended, engages theinterior of the tubing 12 to perform the cutting operation on the tubing12. It will be understood that instead of the toothed outer edge formillustrated, the cutter blades 94 may comprise segments of a circulargrinder of any suitable material that will function to perform thecutting operation. When the cutter blades 94 are assembled in the sixpositions illustrated by the elongated members 88 in FIGURE 3, it can beappreciated that a substantially circular cutter is formed.

The centralizer assembly 66, in addition to the body 72, includes aplurality of radially spaced, resilient centralizer members 96 that aresized to slidingly engage the interior of the tubing 12, thereby holdingthe tubing cutter 10 substantially centered in the tubing 12. Thecentralizer members 96 are disposed in slots 98 formed in the body 72and are each connected to the body 72 by a pair of threaded fasteners100.

Operation When it is desired to sever the tubing 12, the tubing cutter10 is connected by the cable 14 with a hoisting apparatus (not shown)located on the surface near the top of the well bore (not shown). Thetubing cutter 10 is lowered into the tubing 12 with the variouscomponents thereof positioned as illustrated in FIGURES 1A and 1B, thatis, in the retracted position. When the blades 94 of the cutters 90 havereached a position in the tubing 12 adjacent the location wherein thetubing 12 is to be cut, the hoisting apparatus (not shown) is stopped,thereby suspending the tubing cutter 10 in the tubing 12.

To sever the tubing 12, the motor 20 is energized, whereby the shaft 36begins to rotate in a clockwise direction as seen in FIGURES 2 and 3when the cutter blades 94 are constructed as illustrated in FIGURE 3. Asa reaction to the rotation of the shaft 36, the motor 20 and cam 28pivot about the bearing 26 and 32 in a counter-clockwise direction sothat the holding dogs 50, which are riding on the surface of the cam 28,are moved relatively outwardly until the pointed outer ends 52 thereonengage the inner wall of the tubing 12. When this occurs, the reactivepivotation of the motor 20 and cam 28 is arrested. Also, it can beappreciated that the tubing cutter is prevented from rotating relativeto the tubing 12 and from moving in a vertical direction relativethereto. Furthermore, the greater the force exerted on the rotatingparts of the tubing cutter 10, the greater will be the reactive forceexerted to hold the dogs 50 in engagement with the tubing 12.

As the motor shaft 36 rotates, the shaft extension 40, the sleeves 78and the connected articulated linkage and cutter assemblies 90 alsorotate. Centrifugal force resulting from the rotation of the cutterassemblies 90 forces the cutter assemblies 90 relatively outwardlybringing the cutter blades 94 into engagement with the interior wall ofthe tubing 12. It will be noted that the articulated linkage providedpermits the cutter blades 94 to move outwardly in a plane disposedperpendicularly to the longitudinal axis of the tubing 12.

As the cutter assemblies 90 move outwardly, a force is imposed on thesleeves 78 through the elongated members 88 moving the sleeves 78relatively together. As the sleeves 78 move together, the spring 84 iscompressed. Continued rotation of the shaft extension 40 results in theformation of a circumferential slot in the tubing 12 as illustrated inFIGURE 1B and ultimately in the severing of the tubing 12.

After the tubing 12 has been severed, the motor 20 is deenergizedresulting in the cessation of rotation of the shaft 36 and the shaftextension 40. As the shaft extension 40 slows down and ceases to rotate,the centrifugal force exerted on the cutter assemblies 90 diminishesuntil it disappears entirely. When and as this occurs, the spring 84returns to its unstressed condition forcing the sleeves 78 relativelyapart. As the sleeves 78 move relatively apart, the cutter assemblies 90are retracted and the elongated members 88 return to the retractedposition illustrated in FIGURE 1B.

Simultaneously, the motor 20 and the cam 28 are returned to the positionillustrated in FIGURE 1A and in solid lines in FIGURE 2 due to therestoring force exerted by the springs 58 on the motor 20 and therestoring force exerted by the springs 56 on the holding dogs 50. Thus,the holding dogs 50 are Withdrawn from engagement with the interior wallof the tubing 12 and the tubing cutter 10 is in condition for withdrawalthrough the tubing 12.

From the foregoing detailed description, it can be appreciated that thetubing cutter 10 is relatively simple in construction. Due to theelimination of the previously used gear drives for the cutters and dueto the elimination of the relatively complex holding mechanismspreviously utilized in wire line supported cutters, it can beappreciated that the tubing cutter 10 can be constructed in a very smalland compact size and can, therefore, be effectively utilized to severrelatively small diameter tubing.

It will be understood that the single embodiment described in detailhereinbefore is presented by way of example only and that many changesand modifications can be made thereto without departing from the spiritof the invention or from the scope of the annexed claims.

What I claim is:

1. In a tubing cutter:

a motor including a rotatable shaft;

holding means responsive to the reaction of said motor for engaging thetubing to prevent rotation of said motor;

a pair of spaced sleeves slidingly disposed on said shaft and rotatabletherewith;

resilient means biasing said sleeves relatively apart;

and,

a cutter assembly located between said sleeves, said cutter assemblyincluding a plurality of segmented cutter members arrangedcircumferentially around said shaft, and

linkage means interconnecting said cutter members and sleeves, wherebysaid cutter members are moved relatively outwardly by centrifugal forceinto cutting engagement with the tubing when said shaft is rotating andare biased relatively inwardly out of engagement with the tubing as saidrotation ceases.

2. The tubing cutter of claim 1 wherein said holding means includes:

a hollow housing member pivotally supporting said motor, said housingmember being arranged for movement through said tubing and having atleast two apertures extending through the wall thereof;

a cam member attached to said motor;

a holding dog slidingly disposed in each said aperture and having oneend in engagement with said cam member, whereby reactive pivotation ofsaid motor and cam member biases said dogs relatively outwardly intoholding engagement with the tubing.

3. The tubing cutter of claim 1 wherein said linkage means includes apair of elongated members having one end pivotally connected with eachof said cutter members and having the other end of each said elongatedmember pivotally connected with a respective one of said sleeves.

4. The tubing cutter of claim 1 and also including centralizer meansjournaling one end of said shaft and arranged to slidingly engage theinterior wall of the tubing to center said tubing cutter therein.

5. The tubing cutter of claim 4 wherein said centralizer means includes:

a body member;

bearing means located in said body member and engaging said shaft,whereby said shaft is rotatable relative to said body member;

connecting means holding said shaft, bearing means and body memberassembled; and,

a plurality of radially spaced, resilient centralizer members connectedwith said body member and pro- -jecting outwardly therefrom for engagingthe tubing.

6. A cutter for severing tubing located in a well bore, said cuttercomprising:

a hollow housing member arranged to be moved through the tubing;

a motor pivotally disposed in said housing member and including arotatable shaft projecting therefrom;

holding means responsive to the reaction of said motor for engaging thetubing to prevent rotation of said motor; and

a cutter assembly operably mounted on said shaft, said cutter assemblyincluding a plurality of segmented cutter members arrangedcircumferentially around said shaft, and

linkage means operably connecting said cutter members with said shaft,whereby said cutter members are moved by centrifugal force, when saidshaft is rotating, into cutting engagement with the tubing.

7. The cutter of claim 6 wherein said linkage means includes:

a pair of spaced sleeves slidingly disposed on said shaft and rotatabletherewith, one of said sleeves being located on each side of said cuttermembers;

spring means engaging said sleeves for biasing said sleeves relativelyapart;

a pair of elongated members having one end of each of said elongatedmembers connected with a respective one of said cutter members andhaving the other end of each of said elongated members connected with arespective one of said sleeves.

8. The cutter of claim 6 and also including:

means connected with said housing member for moving said cutter throughthe tubing; and,

centralizer means journaling one end of said shaft and arranged toslidingly engage the interior wall of the tubing to center said cuttertherein.

9. A cutter for severing tubing located in a well bore,

said cutter comprising:

a hollow housing member arranged to be moved through the tubing andhaving at least two apertures exending through the wall thereof;

a motor pivotally disposed in said housing member and having a rotatableshaft projecting from said motor;

a cam member attached to said motor and pivotal therewith;

a holding dog slidingly disposed in each said aperture and having oneend in engagement with said cam member, whereby reactive pivotation ofsaid motor and cam member biases said dogs relatively outwardly intoholding engagement with the tubing to prevent rotation of said motorrelative to said housing member and to prevent movement of said cutterrelative to the tubing;

a shaft extension having one end connected with said motor shaft;

a centralizer assembly spaced from said body member and journaling theother end of said shaft extension;

a pair of spaced sleeves slidingly disposed on said shaft extension,said sleeves being rotatable with said shaft extension;

spring means encircling said shaft extension between and in engagementwi'h said sleeves for biasing said sleeves relatively apart; and,

a. cutter assembly located between said sleeves, said cutter assemblyincluding a plurality of segmented cutter members arrangedcircumferentially around said shaft extension, and

flexible linkage means interconnecting said cutter members and sleeves,whereby said cutter members are moved relatively outwardly bycentrifugal force into cutting engagement with the tubing when saidshaft extension is rotating and are biased relatively inwardly out ofengagement with the tubing by said spring means when said rotationceases. 10. The cutter of claim 9 and also including: means connectedwith said housing member for moving said cutter through the tubing; andwherein said centralizer assembly includes a body member, bearing meanslocated in said body member and engaging said shaft extension, wherebysaid shaft extension is rotatable relative to said body member,connecting means holding said shaft extension, bearing means and bodymember assembled, and a plurality of radially spaced, resilientcentralizer members connected with said body member and projectingoutwardly therefrom for slidingly engaging the tubing to center saidcutter therein.

References Cited UNITED STATES PATENTS 1,358,818 11/1920 Bering 16655.71,498,463 6/1924 McCloskey et a1. 175-285 2,280,769 4/1942 Page 16655.7X 2,638,801 5/1953 Klaasen et a1. 16655.7 X

DAVID H. BROWN, Primary Examiner.

6. A CUTTER FOR SEVERING TUBING LOCATED IN A WELL BORE, SAID CUTTERCOMPRISING: A HOLLOW HOUSING MEMBER ARRANGED TO BE MOVED THROUGH THETUBING; A MOTOR PIVOTALLY DISPOSED IN SAID HOUSING MEMBER AND INCLUDINGA ROTATABLE SHAFT PROJECTING THEREFROM; HOLDING MEANS RESPONSIVE TO THEREACTION OF SAID MOTOR FOR ENGAGING THE TUBING TO PREVENT ROTATION OFSAID MOTOR; AND A CUTTER ASSEMBLY OPERABLY MOUNTED ON SAID SHAFT, SAIDCUTTER ASSEMBLY INCLUDING A PLURALITY OF SEGMENTED CUTTER MEMBERSARRANGED CIRCUMFERENTIALLY AROUND SAID SHAFT, AND